This invention relates to textile fiber processing machines, such as cards, cleaners or the like and is more particularly concerned with an apparatus for measuring the clearance between clothings of two cooperating components such as a clothed roll and a clothed countermember, such as a travelling flat bar. The apparatus includes at least one sensor which determines the clearance between two clothings, that is, it detects the distance between the points of one clothing on the one hand and the points of the other clothing, on the other hand.
In the assembling operation of carding machines, a predetermined distance between the clothed main carding cylinder and the flats, for example, the travelling flats is set manually with the aid of templates. Such an adjusting operation also sets, at the same time, the clearance between the points of the carding cylinder clothing and the points of the flat clothing. During operation, centrifugal forces and thermal expansions alter the distance between the carding cylinder and the flats and thus, likewise, the clearance between the clothing points of the carding cylinder and the flats varies. Such a change is, as a rule, taken into consideration during the manual setting.
In a known apparatus, between the clothed carding cylinder and the clothed flats cooperating therewith at least on one side of the carding cylinder, externally of the clothing respective sensors are positioned for monitoring, during operation, the set distance between the carding cylinder and the flats. The distance is always measured from the carding cylinder. On the flats, opposite the carding cylinder, counter members are associated with the sensors. Upon changes caused by centrifugal forces and thermal expansions during operation the distance between the sensor and the counter member diminishes and thus, during operation, the known apparatus may directly measure the altered distance between the carding cylinder and the flats. In case the clothing has been replaced by a new clothing that is, there is no wear-caused change of the point height of the clothings--a change of the originally set distance between the clothing points of the carding cylinder and the clothing points of the flats may be indirectly determined. Such a conventional arrangement is disadvantageous in that during operation the actual distance between the clothing points cannot be measured after an extended run of the machine. The point height of the clothing is reduced because of wear so that the distance between the carding cylinder and the flats on the one hand and the distance between the facing clothing points on the other hand become increasingly independent from one another as the service period increases. It is a further disadvantage that measuring a change of the clothing point height of the carding cylinder clothing is not possible after an extended operational period.